1. Technical Field of the Invention
The present invention relates generally to a behavior control apparatus for vehicles which monitors the behavior of a vehicle body and automatically regulates the braking effort applied to each wheel to control the behavior of the vehicle body.
2. Background Art
Japanese Patent First Publication No. 9-226555 discloses an automatic brake control system for vehicles designed to control brake pressure (i.e., wheel cylinder pressure) applied to each wheel as a function of traveling conditions of the vehicle. This system monitors the lateral acceleration acting on the vehicle, the direction of a turn, and the brake pedal effort produced by a vehicle operator to determine a target wheel speed of a compliance one of outside wheels during turning based on the speed of a front one of inside wheels and the lateral acceleration when no brakes are applied and to determine a target wheel speed of a front one of inside wheels during turning based on the speed of a front one of the outside wheels and the lateral acceleration when the brakes are being applied and the braking force applied to the wheels according to one of the target wheel speeds. In brief, a control reference value used in controlling a speed difference between the outside and inside wheels during turning based on the lateral acceleration is switched between states of applying the brakes and applying no brakes, thereby bringing the rotation of the right and left wheels into a preselected condition, e.g., by adjusting the speeds of the right and left wheels to have the same slip ratio for stability of vehicle motion.
The above conventional system, however, does not estimate a vehicle condition in the automatic brake control and may encounter the problems that the automatic brake control causes the deterioration of vehicle behavior and/or the lack of braking force. Specifically, when the automatic brake control is carried out without taking a dynamic balance of the whole of a vehicle body into account in determining a target controlled state of each wheel, it may cause the dynamic balance of the vehicle body or vehicle behavior to be deteriorated.